[Wasm] stdlib API: make kotlin.assert internal

Being disabled by default
 and not well-documented, these functions cause confusion among early
 adopters as to why their code don't work properly.

Assert APIs need a proper design across Kotlin platforms.
 Since APIs are not available in common code and K/JS, it is premature
  to have such a general feature in a new experimental platform.

Compiler tests:
* Mute tests that rely on assert.
* Replace JVM-specific assert calls with require calls and unmute passed K/JS tests.

Merge-request: KT-MR-8636
Merged-by: Svyatoslav Kuzmich <svyatoslav.kuzmich@jetbrains.com>

compiler/testData/codegen/box/casts/functions/reifiedIsFunKBig.kt

@@ -43,7 +43,7 @@ inline fun <reified T> assertReifiedIs(x: Any, type: String) {
     catch (e: Throwable) {
         throw AssertionError("$x is $type: should not throw exceptions, got $e")
     }
-    assert(answer) { "$x is $type: failed" }
+    require(answer) { "$x is $type: failed" }
 }
 
 inline fun <reified T> assertReifiedIsNot(x: Any, type: String) {
@@ -54,7 +54,7 @@ inline fun <reified T> assertReifiedIsNot(x: Any, type: String) {
     catch (e: Throwable) {
         throw AssertionError("$x !is $type: should not throw exceptions, got $e")
     }
-    assert(answer) { "$x !is $type: failed" }
+    require(answer) { "$x !is $type: failed" }
 }
 
 abstract class TestFnBase(val type: String) {